Modern data processing systems require that a substantial portion of the information stored in its memory be randomly accessible to ensure rapid access to such information. Such randomly accessible devices include ferroelectric random access memories (FRAMs). FRAMs exhibit significant advantage of being nonvolatile which is achieved by virtue of the fact that a ferroelectric capacitor includes a pair of capacitor plates with a ferroelectric material between them which has two different stable polarization states which can be defined with a hysteresis loop depicted by plotting the polarization against applied voltage.
A method for using a ferroelectric material between two electrodes is taught in U.S. Pat. No. 5,728,603 entitled "Method of forming a crystalline ferroelectric dielectric material for an integrated circuit" by Emesh et al., which is hereby incorporated herein by reference.
Though the above mentioned patent relates to perovskite formation by varying post-annealing condition, formation of nonpolar pyrochlore phase formation was obtained.
Since the pyrochlore can be formed in the formation of the ferroelectric dielectric film with crystalline perovskite structure by the process of depositing a layer of amorphous ferroelectric precursor material and then annealing, it is required to remove the nonpolar(non perovskite) phase including pyrochlore following the annealing process from a top surface of the ferroelectric dielectric film.